[3.11] gh-103417: Fix the scheduler example (GH-111497) (GH-115909)

Arguments to enterabs() are specified as Unix time.
If the scheduler use the time.monotonic timer, the code will take
decades to complete.
(cherry picked from commit cb287d342139509e03a2dbe5ea2608627fd3a350)

Co-authored-by: mauricelambert <50479118+mauricelambert@users.noreply.github.com>